Since JDK8u60 b14 transparency is enabled in 3D shapes.
This is a quick test done with it:
A cylinder with diffuse color Color.web("#ffff0080")
, is added on top of a box and two spheres.
group.getChildren().addAll(sphere1, sphere2, box, cylinder);
There’s no depth sort algorithm though, meaning that order of how 3D shapes are added to the scene matters. We need to change the order to allow transparency in the box:
group.getChildren().addAll(sphere1, sphere2, cylinder, box);